I would like to build a compost for our coffee grounds. In my understanding we are going to need more diversity of organic material than just coffee, like leaves and other organic waste, which we don't have a whole lot of compared to all the coffee. How about a worm compost? Does anyone have a big coffee grinds compost working out for them?

i bet your cafe(s) easily produce enough organic waste to supplement the grinds. eggshells are an excellent thing to mix with grounds as a liming substitute for gardens. eggshells are mostly calcium carbonate and both shells and coffee contain nitrogen and phosphoric acid. add some of that chaff from some friendly roaster and all that other wet organic stuff you throw in the garbage. some leaves are better than others. google it.

obviously, if it's too much coffee it'll get too acidic. you can do a ph test on your compost or just common sense it.

You can find some dead leaves lying around I'm sure...Green versus Brown - Nitrogens and Carbons. . . If I remember correctly coffee grounds fall into the green/nitrogen category. I believe paper filters will fall into the brown/carbon category.

I've looked into this enough now where I should remember more basics, but no - - -

Old newspaper, brown paper bags, corrugated cardboard, and toilet paper/paper towel rolls would all be great compliments to the coffee grounds in your bin. Just make sure it is in small, bunched up and/or torn up pieces rather than in compacted dense layers. The toilet paper/paper towel rolls can get thrown in just as they are.

thanks for the advice. the wooden shipping pallets seem like a good idea... i need to build something with a top to keep out rain and it needs to be rodent proof. what sort of materials would you suggest? I presume some sort of opening in the bottom would be ideal to eventually remove compost, or does that really matter?

The half-assed construction of my example is what bothers me most. This is only because for me to remove the front wall (which I do perhaps monthly or bi-monthly for proper turning over of the pile) I have to then work a bit harder to push the pile back so as to shimmy the front wall back in place. I'm only bending a side wall a little out, pushing the front wall in, and bringing the side wall back to hold the front wall in place. As I said, half-assed. But it works. I merely have a large top board I put on top and keep weighted down with the shovel that I remove, dig/turn every few days, and carry on. It's working and things are going well - the anxiety to remove any product is completely gone and I can only really think about how much better my mixture gets as things continue to decompose.

If I could do it again (and when I have to move I'm taking this pile with me) I would use cinder blocks, create something a little bigger and certainly something with a door thats easier to remove so I can turn the pile more completely.

We're out in the burbs with a lot of small animals but haven't had a problem with anything getting into our bin. It's a butt-ugly, totally illegal (in our township) three bin, about 3' deep, 3' tall (slopes to 4'), 8' wide. Basically a fortified frame of 2x4s lined with chicken wire. Instead of a door that lifts up like Scott's, it has side-hinged doors that close with a simple hook and eyescrew, so it's not that difficult to shove the stuff back in and get the doors closed. The top is just plywood, also hinged in back (which unfortunately tends to warp from time to time), so you have access from both top and front. Pretty much built the thing using wood leftover from other projects. Not a hard project.